Heretofore in the prior art, various safety switches have been used to prevent accidental starting of the power tool. However, whenever a chuck key was used in the safety switch, it would be to make or break the actual circuit contacts of the safety switch. A second on-off switch was required to operate the power tool. The use of a second safety switch was disadvantageous in that it was another component which added to the cost and complexity of the tool and might itself adversely affect the safe operation of the tool by permitting the insertion of the chuck keys at such times when the on-off switch was in the on position, thus the safety switch would be actuated by the insertion of the chuck key to suddenly start the power tool.